corps (n.)

late 13c., cors "body," from Old French cors "body, person, corpse, life" (9c.), from Latin corpus "body" (from PIE root *kwrep- "body, form, appearance"). Sense in English evolved from "dead body" (13c.) to "live body" (14c.) to "body of citizens" (15c.) to "band of knights" (mid-15c.). The modern military sense (1704) is from French corps d'armée (16c.), picked up in English during Marlborough's campaigns.

French restored the Latin -p- in 14c., and English followed 15c., but the pronunciation remained "corse" at first and corse persisted as a parallel formation. After the -p- began to be sounded (16c. in English), corse became archaic or poetic only.

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